Add OVERRIDE to chrome/browser/.

chrome/browser/tabs/tab_strip_model.h

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROME_BROWSER_TABS_TAB_STRIP_MODEL_H_
 #define CHROME_BROWSER_TABS_TAB_STRIP_MODEL_H_
 #pragma once
 
 #include <vector>
 
@@ skipping 454 matching lines @@
   std::vector<int> GetIndicesClosedByCommand(int index,
                                              ContextMenuCommand id) const;
 
   // Returns true if 'CommandTogglePinned' will pin. |index| is the index
   // supplied to |ExecuteContextMenuCommand|.
   bool WillContextMenuPin(int index);
 
   // Overridden from content::NotificationObserver:
   virtual void Observe(int type,
                        const content::NotificationSource& source,
-                       const content::NotificationDetails& details);
+                       const content::NotificationDetails& details) OVERRIDE;
 
   // Convert a ContextMenuCommand into a browser command. Returns true if a
   // corresponding browser command exists, false otherwise.
   static bool ContextMenuCommandToBrowserCommand(int cmd_id, int* browser_cmd);
 
  private:
   // Gets the set of tab indices whose domain matches the tab at |index|.
   void GetIndicesWithSameDomain(int index, std::vector<int>* indices);
 
   // Gets the set of tab indices that have the same opener as the tab at
@@ skipping 167 matching lines @@
 
   // A scoped container for notification registries.
   content::NotificationRegistrar registrar_;
 
   TabStripSelectionModel selection_model_;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(TabStripModel);
 };
 
 #endif  // CHROME_BROWSER_TABS_TAB_STRIP_MODEL_H_